Hope M4 Queries

[Nuffy]

I have an old Hope M4 brake that I'm using on the front of my bike. It's quite a monster, but I'm not happy with the lever movement. I have to pull the lever a long way before it bites (which it does quite nicely). I tried making some spacers to put between the pads and the pistons, and this seemed to help (although the material I used was not ideal, so made it a bit mushy). After a while it was back to it's original state, so I put in some bigger spacers, thinking it was just pad wear. Again, the material I was using (emery paper or something) made it mushy. I haven't managed to get some thin enough steel or something to use instead.

 

Having looked at the website and owner's manual, however, I have established that the open system should automatically compensate for pad wear. So is this why it returned to its original state? I have removed all the spacers now in the hope that it will readjust itself, but nothing yet (i.e. still way too much lever movement). I have bled it several times, so I'm confident that it's not due to air in the system. Do I just need to use the brake a bit more for it to come right? Apart from the spacer method, is there any way of adjusting the bite point? It would seem not.

 

Any help would be appreciated.

[The Saint]

Luckily for me I have no idea what the hell you are talking about.

 

But if I have to dispense some advise here goes - Get a new Hope M4 brake.

 

Actually come to think of it considering that you are putting emery paper in your brakes I would have to hazard a guess that you drive one of those Toyota Hilux Taxis that take 30 people for a living.

MuXmAn2007-11-03 10:58:32

[Joe Low]

Muxy - how many beers you on & where'd you disappear to this morning?

 

Nuffy - super-technical query that the 13 of us currently online are struggling to help with.

 

If you don't get any joy over the weekend, bump the post on Monday morning when there's over 100 of us on and you are bound to make some anorak's day - I'm betting there's a load of IT hubbers who will inundate you with advice, they seem to love your sort of problem.

 

Good luck

 

 

[Nuffy]

 

Well, you gave me a good laugh if nothing else, MuXmAn, so thanks!

 

The M4 is a hydraulic disc brake made by Hope, a UK company. The problem with my particular one is that I have to pull the brake lever a long way before the brake "bites" and slows me down. I'm just trying to work out how I can remedy this. A look at the owner's manual,

 

(http://www.hopetech.com/database/userguide_printed_2002.pdf)

 

shows that the "open" system used on this brake (I won't go into the details of that now) should automatically ensure a constant bite point, and it cannot be adjusted. Some fiddling on my part (with spacers, as mentioned above) has shown that some adjustment can be made, but it may be temporary and has proven unsatisfactory so far. I'm just trying to figure out if the brake will adjust itself if I leave it be, or if there is something wrong that I can fix.

 

A new Hope M4 Brake will cost well above R1000, I suspect, and so is out of my price range for now. Besides, I think it's much better to fix what I have if I can.

 

Anyhow, I hope that clears up any confusion. If you're a roadie and have never encountered a hydraulic brake before, don't confuse yourself too much. There's a lot more to it than meets the eye.

 

Joe Low - thanks, I'll try that. It is a bit fiddly, and with any luck I'll have figured it all out by then.

 

Nuffy2007-11-03 11:17:22

[SwissVan]

 

Nuffy - Being a v brake constituent I dont know for sure BUT... I would expect there to be some sort of adjustment on the brake lever mechanism (not down at the caliper) which you could screw in / out more to take up the extra lever movement thus applying the brake sooner. 

 

[Nuffy]

SwissVan - yeah, having just upgraded from V-brakes myself I would have thought so too, but it seems that bite point adjustment is a relatively new thing on closed system hydraulic discs. The only adjustment on the lever is for the lever reach, which changes the position of the lever relative to the bars, but has no effect on the amount of movement or bite point.

 

I have another question as well: There is a tiny hole in the side of the reservoir at the top. I assume this is to allow expanding/overheating fluid to escape. Am I correct? Should it be spluttering when I pump the lever? The membrane seems undamaged, and having taken it apart and bled it several times I'm confident that it's not just sitting squif or something.

 

[linnega]

I wouldn't think that fluid sputtering out is normal and the purpose seems correct.

 

I'm sure there must be some sort of adjustment for lever movement.  Some grips would make it impossible to fully compress the lever if it is as "loose" as you are describing.  Is there nothing in a dark crevice behind the lever.  On the Avid's the adjustment screw is so small I struggled to find an Allen key small enough to use for adjusting it!

 

[Zaskar]

Is this the one you have?

 

With the mini lever?

I have one that i used for about a year on a bike, and it never gave a days trouble. i never had to bleed it, or do anything other than change the pads. But i think you are right, there is no screw or anything for adjustment (except for reach), the only way i ever was able to change the amount of lever movment before it bit was to add more fluid. I cant really help you more than that, but maybe take it in to one of the Hope dealers to get some advice? Or just email them directly, i seem to remember they replied to me once the same day on a query i had! Im sure they will help you out.

 

But if you still dont come right, ive got mine lying in a box at home, and you are welcome to make me an offer on it. Its a no 8 Caliper (205mm rotor) and i have 2 brand new sets of pads, and 2 rotors for it. Its in the box and ready to go.

 

[tyrone]

I have been battling to get pads for my Hope M4's. Any chanse you want to sell just the pads on there own.

 

Tyrone

[MintSauce]

nuffy....I'm no expert but from what I know it's definitely not normal for it to be spitting out fluid. Don't know about Hope but my Avids use normal brake fluid and believe me, you don't want that stuff anywhere but inside the brake! It will wreck your paint and clothing if it comes into contact!

 

It sounds to me like you have a leak(the spluttering) and the loss of fluid is what is causing the extra travel at the lever.

 

Speak to Lance at The Epic Bike Shop in Plumstead

http://www.epicbikeshop.co.za/

 

He recently fitted Hope Mono Minis to his bike and is/will be stocking Hope parts. He's a great guy and will be happy to help!

 

 

 

 

[#Pete#]

If the 'bite point' is late you must have too little fluid in or a leak somewhere in the system.

 

You never need to space the pads or adjust the lever in any way.

 

Which levers are you using? How are you bleeding?

 

[Nuffy]

 

Is this the one you have?

 

With the mini lever?

 

 

Zaskar - Yep, that's it. Thanks for the offer, but apart from the lever movement it seems to be working perfectly, so I'm not looking to replace it. And as for your idea of more fluid - I've bled it several times and filled it up good and proper. Maybe I should see if I can move the pistons inwards and then add more fluid; but the owners manual says the pistons should be fully retracted when bleeding.

 

MintSauce - thanks, if I don't get it sorted I may pay them a visit. I'm wondering if perhaps the spluttering is just a temporary thing while it settles in after bleeding and gets rid of excess fluid, but I'm not sure.

 

I've been bleeding exactly as the manual describes - attach a hose to the bleed nipple, open up the reservoir, open the bleed nozzle, pull the lever in, close the nozzle, let the lever out and top up the reservoir as the fluid goes down. I put some tyre leavers between the piston to keep them apart, as described in the manual.

 

I'm pretty confident that there are no leaks in the system (the hose and fittings are brand new, and I have watched them closely). And since the hole from whence the spluttering is happening is on the reservoir, surely it wouldn't affect the lever movement (as the master piston has moved past the feeder from the reservoir a short way into its travel)?

 

It may have something to do with the rotor I am using. It is a Hayes one, and is a good deal thinner than my Magura one at the back (1,25mm, I think). Could it be that the pistons are not designed to move in that much? I would have thought that the automatic pad wear adjustment would have compensated for this, but perhaps not. Any idea how thick the Hope discs are?

 

Anyhow, thanks for all the help. It's not a major breakdown, just an annoyance. I'll go and tinker some more.

 

[Guest Big H]

Nuffy, contact Alan at International Trade in Midrand @ tel no +27 11 452 6587 or at laudin@branell.com at  

 

The Hope Mono 4 is a four pot disk brake (same as racing cars and bikes) with self adjusting disk pads as you mentioned. Please do not use emery paper in your brake equipment as this is sandpaper!!!!! Not very condusive to aluminium and other soft metals I would think!!!!!

 

I have this brake with 180 mm rotors on the tandem. Our brakes are in black.

 

Hope Mono M4 Moto Disc Brake Rear Lever - New lightweight lever giving smooth, progressive feel and more power. Split clamp for easy fitting. Integrated master cylinder reservoir for easy bleeding. Adjustable lever reach. Black hose as standard. Caliper - One piece caliper, machined from solid billet of aluminium with stiffer caliper bridge. As well as reducing weight, this also allows us to make a more rigid caliper, improving the lever feel. Silver caliper with black bore caps allowing access for servicing. Caliper pistons are now made from phenolic to isolate the caliper from the heat generated in the pads. Use - Heavy Cross-country + All Mountain Weight Inc mount, all bolts and disc - from 437g

http://www.chainreactioncycles.com/Images/Models/Full/15618.jpg

 

I will measure some new disks I have at home tonight.

 

I have a bleed kit that uses tyre presuure to force the hydraulic fluid through the system form the bleed nipple end.

 

You can also get spares and the bleed kit from www.chainreactioncycles.com

 

 

Big H2007-11-05 10:06:10

[#Pete#]

The rotors are 1.5mm I think, but thinner ones work.

 

assuming all is fine - try one of these methods to set the pads:

1. Take out wheel, pull the lever tight and hold for a few seconds twice, then insert disc - should be tight.

2. Leave in wheel, but pull lever tight overnight with elastic vand or something similar.

 

 

[Nuffy]

 

Cool, thanks guys. I have put my spacers back in and things are much better, but still a little squishy (the emry paper is slightly compressable). I'll see if I can find something more suitable.

 

Big H, since they are just acting as spacers and there is no back and forth movement, I don't see the emry paper causing any damage, but I will try to get some proper steel or something if I don't sort it out any other way. I have put two pieces facing each other between the pads on one side and the pistons, so there's no contact with the rough side and any brake parts.

 

That sounds like a pretty cool bleed kit - I think I would bleed my brakes daily with that! Thanks for the contacts and link. I don't have money to spend on spares, and don't think I need anything specific yet.

 

#Pete#, I have tried your number 2 suggestion with no luck, so will try number 1 when I get back home.

 

If that doesn't work, I think I'll get some nice spacers laser cut from steel. If it's done properly it should be good. So it would seem that the thin rotor (1,52mm min, it says, not 1,25mm as I said earlier) may be the problem. At any rate, the spacers seem to do the trick.

 

Thanks for all the help.

Nuffy2007-11-05 14:53:30